Electronic pain control has provided an effective and widely successful mode of patient treatment, particularly for chronic and post-operative pain conditions. While the circuitry and signalling aspects of electronic pain control are reasonably refined, electrode design and construction continues to be an area ripe for development and improvement. Hence, while it is generally understood that factors of patient comfort, electrode flexibility, electrode adhesive and removability characteristics, uniformity of electrical current density, and the like parameters are desirable design goals, most designs involve compromises or tradeoffs between the respective factors, with most electrodes involving relative strengths in some aspects but consequent disadvantages in others.
It is a principal object of the present invention to provide electrodes for electronic pain control applications, which have superior overall performance characteristics.
One class of electrode is exemplified in U.S. Pat. No. 4,066,078 to Berg, setting forth an electrode having an electrically conductive polymer adhesive gel, and a suitable non-conductive backing, whereby the gel is directly coupled to the skin of the patient. Another type of electrode is exemplified by U.S. Pat. No. 4,125,110 to Hymes, utilizing karaya gum as the electrically conductive patient interface, suitably backed by non-conductive material.
Many of the known electrodes either of the type exemplified by the Berg patent, or of the type exemplified by the Hymes patent, exhibit the lack of ability to "breathe", that is, the ability to be able to dissipate absorbed moisture which is absorbed from the skin. Often, if electrodes do not have this "breathing" ability, actual physical swelling of the electrode occurs, with consequent uncertainty as to the physical dimensions and correspondingly the electrical characteristics of the material as an electrode.
It is accordingly an object of the present invention to provide electronic pain control electrodes wherein absorbed moisture, obtained either from the skin of the patient or from the ambient atmosphere, is effectively dissipated while dimensional and electrical stability is maintained.
Another difficulty often associated with electrodes of the types aforementioned is mechanical adhesion of the gelatinous pad to the non-conductive backing. During removal or adjustment of the electrode relative to the skin, the pad experiences tension and shear forces caused by the lifting of the backing material, which forces are distributed to the skin-pad and the pad-backing interfaces.
It is accordingly an object of the present invention to provide electrodes which, while functionally superior from the standpoint of comfort, adhesionability, and moisture dissipation characteristics, are furthermore possessed of superior structural strength whereby tension and shear forces encountered in removal or the like operations, have minimal effect in altering the physical and electrical characteristics of the electrode.